New ER Protocol Encourages use of Blood Tests for Heart Attack Diagnosis

Anahita Kodali, Medical Sciences, News, Spring 2020

Figure 1: Heart attacks are caused because blood cannot get to the heart. As shown in this image, plaque (the yellowish-orange substance) develops in the arteries and clogs them. If this plaque ruptures, blood clots; this means it cannot travel to the heart to give the heart necessary nutrients and oxygen, causing damage.

Image Source: Wikimedia Commons

Every 40 seconds, someone in the US has a heart attack1. Heart attacks occur when blood flow to the heart is blocked by plaque formation in the coronary arteries. This plaque is caused by a buildup of fat and cholesterol (see Figure 1); when this plaque ruptures, blood clots, causing the heart attack. There are several warning symptoms, including pressure and pain in the chest and arms and profuse sweating. However, these “normal” symptoms are not always present – some people have mild pain, and some people have no pain at all2. Sometimes individuals that suffer heart attacks, and this more common in women, experience atypical symptoms, like nausea, shortness of breath, fatigue, and dizziness3. This makes it difficult to determine whether or not someone is actually having a heart attack, even while they are seeking medical services, delaying their treatment by medical professionals. When heart attacks are left untreated, the heart can suffer permanent damage and the patient can die, so it is imperative that they are diagnosed quickly and are treated as fast as possible.

Now, researchers at the University of Texas Southwestern Medical Center have laid out a new protocol to test patients for heart attacks in the ER. The protocol they describe relies on testing for troponin. Troponins are part of the group of proteins that help modulate the contractions of the heart and all skeletal muscles. There are three different types of troponin: troponin I, C, and T. Troponin C binds calcium and transports troponin I, which helps muscles relax. Troponin T binds cardiac and skeletal proteins to muscle fibers, allowing muscles to contract. All three are vital to the movement process, but troponin tests generally check for troponin I or troponin T levels. Normally troponin levels in the blood are very low, but research has shown that when the heart is in distress or is being damaged, it releases troponin. Thus, very high levels of troponin indicate a heart attack5.

The group at UT Southwestern Medical Center found that doctors can use very sensitive cardiac troponin testing to determine which patients are, and are not, having a heart attack. By combining this test with other parts of the HEART score (history, electrocardiogram, age, risk factors, and troponin), a tool regularly used by ER departments to allow patients to be discharged, doctors are able to process patients who may be having a heart attack and clear overcrowded ERs5. In several interviews with ScienceDaily, the co-author of the study and professor of internal medicine at UT Southwestern James de Lemos talked about the team’s remarkable results – in over half the tests they had performed under this protocol, physicians were able to rule out heart attacks in under an hour. Cardiologist Rebecca Vigen, the head of the team, explained that with the COVID-19 pandemic causing overcrowding in hospitals and fear for entering ER rooms, it is critical to quickly assess patients and get them the care that they need6.

Hopefully, as this protocol gets adopted by ER departments around the country, the numbers of patients held up in ER rooms for multiple hours drops, and patients feel more safe coming to the ER

 

Bibliography

[1] Heart Disease Facts. (2019, December 2). CDC. Retrieved from https://www.cdc.gov/heartdisease/facts.htm

[2] Heart attack. (2018, May 30). Mayo Clinic. Retrieved from https://www.mayoclinic.org/diseases-conditions/heart-attack/symptoms-causes/syc-20373106

[3] Harvard Health Publishing. (n.d.). When heart attacks go unrecognized. Harvard Health Publishing. Retrieved from https://www.health.harvard.edu/heart-attack/when-heart-attacks-go-unrecognized

[4] Villines, Z. (2019, June 7). Normal troponin levels: What high levels mean, plus causes. Medical News Today. Retrieved from https://www.medicalnewstoday.com/articles/325415#why-do-doctors-test-troponin-levels

[5] Vigen, R. et. al. (2020). Association of a Novel Protocol for Rapid Exclusion of Myocardial Infarction With Resource Use in a US Safety Net Hospital. JAMA Network Open 3(4): e203359 DOI: 10.1001/jamanetworkopen.2020.3359

[6] UT Southwestern Medical Center. (2020, April 22). New heart attack testing protocol expedites treatment in ER. ScienceDaily. Retrieved April 25, 2020 from www.sciencedaily.com/releases/2020/04/200422214051.htm

 

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